Fix PCLZIP_ERR_BAD_FORMAT (-10) Error

What this means

PCLZIP_ERR_BAD_FORMAT (-10) is WordPress's way of saying "I can't extract this zip file." It pops up when:

1. The zip file is corrupted or incomplete
2. The zip isn't actually in zip format (sometimes Mac Safari unzips it automatically and renames the folder .zip)
3. Your server is out of memory and gave up mid-extract

Solution 1 — Get a fresh copy

The most common cause is a corrupted download. Re-download Linkilo (or whatever plugin you're uploading) from your Linkilo account → Download History.

If you're on Mac, also see Stop Safari from automatically unzipping files — Safari can silently unzip the download, turning the file into a folder named linkilo.zip that isn't actually a zip.

Solution 2 — Increase PHP memory

Edit wp-config.php and add this line before / That's all, stop editing! /:

define('WP_MEMORY_LIMIT', '256M');

Save and retry the upload.

If you can't edit wp-config.php, contact your host and ask them to raise the PHP memory limit. Most hosts can do this within minutes.

Solution 3 — Try a different upload route

Instead of WordPress's plugin uploader:

1. Extract the zip on your computer (you'll get a linkilo folder)
2. Connect via FTP
3. Upload the entire linkilo folder into /wp-content/plugins/
4. In WordPress: Plugins → Installed Plugins → Activate Linkilo

This bypasses PCLZIP entirely.

Solution 4 — Deactivate other plugins

Sometimes a security plugin (Wordfence, iThemes) scans the uploaded zip and trips this error. Deactivate them temporarily, upload, then reactivate.